Islington Council is considering a judicial review of the decision and has been sounding out other local authorities, including Lewisham and neighbouring Southwark.

An Islington Council spokesman said: "The council is considering a judicial review of the mayor's decision, which we anticipate will be supported by a number of other councils."

A spokesman for Lewisham Council, which recently celebrated a legal victory with the local hospital, said they "have not yet taken a view" on the legal case. It is not yet known what Greenwich Council's position is.